The present invention generally relates to semiconductor integrated circuits, and more particularly, to the structure and formation of vertical metal-insulator-metal capacitors in the semiconductor integrated circuits.
Various capacitive structures are used as electronic elements in integrated circuits such as radio frequency integrated circuits (RFIC), and monolithic microwave integrated circuits (MMIC). Such capacitive structures include, for example, metal-oxide-semiconductor (MOS) capacitors, p-n junction capacitors and metal-insulator-metal (MIM) capacitors. A MIM capacitor typically includes an insulating layer, such as a PECVD dielectric, disposed between lower and upper electrodes. MIM capacitors are typically used to store a charge in a variety of semiconductor devices, such as mixed signal and analog products. For some applications, MIM capacitors can provide certain advantages over MOS and p-n junction capacitors because the frequency characteristics of MOS and p-n junction capacitors can be restricted as a result of depletion layers that form in the semiconductor electrodes. Furthermore, MIM capacitors are formed in the metal interconnect layers, thereby reducing CMOS transistor process integration interactions or complications.